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Diversity and participatory crop improvement as conduit for climate change adaptation

Partners under the theme on Agrobiodiversity, Seeds and Climate Change highlight key learnings from their activities, as shared and discussed at a recent workshop in Zimbabwe

This thematic group within the ISSD Africa CoP has focused its activities on three key topics: the promotion of crop diversity/diversification as an effective strategy to adapt to climate change for smallholder farmers; the establishment and strengthening of community seed banks as platform for community-based rural development; and the design of policies in support of farmers’ seed systems.

At a recent workshop in Harare (17-19 May 2022), hosted by Community Technology Development Organisation (CTDO) of Zimbabwe (one the ISSD Africa partners), work in progress on these three themes was presented and discussed. We report on the first two themes, diversity, and community seed banks, with examples of work from Kenya, Tanzania, Uganda and Zimbabwe. In a blog to be published in the near future, we will report on the policy theme.

Diversity and participatory crop improvement as conduit for climate change adaptation

Farmers have since time immemorial shared local seeds and related knowledge to practice agriculture and produce food and fodder. However, in recent decades notable changes in climate have affected agricultural production, rendering part of the knowledge and seeds passed on through generations less useless. Changes in total amount of rainfall, rainfall distribution, and temperatures, have seen crops and crop varieties grown in communities for hundreds of years suddenly failing. As a result, communities across the world which rely solely on agriculture as a means of survival are suffering.

Smallholder farmers in many parts of Africa are facing uncertainties and increased risks to produce enough food for their families. This situation is exacerbated by limited access locally adaptable varieties that can better respond to the changing climatic and environmental conditions. Most seed available on the market is produced by large commercial seed companies that do not cater to the needs of smallholder farmers operating in diverse climatic, agro-ecological and environmental conditions, and growing a diversity of crops (not only maize!), including so-called neglected and underutilized species, e.g. minor millets, pulses, traditional herbs and vegetables.

The multiple benefits of diversity

Diversity among and within species provides insurance or a buffer against environmental changes, because different species and varieties occupy different niches and respond differently to change. If one crop species does not perform well or fails, another or others can come to the rescue. The harvest may not be totally lost and (partially) saved. At the eco-system level, when species outnumber functions, redundancy emerges, which facilitates overall ecosystem functioning and the provisioning of ecosystem services. Thus, agrobiodiversity fosters ecological resilience. When this principle is applied to crop diversification—the cultivation of different crop species and/or varieties in a season or over several seasons— farmers can achieve stable and diverse food production, which in turn, can contribute to dietary diversity and income generation, and reduce risks from climate variability, diseases, pests, and market changes. Crop diversification could also improve the management of other natural resources, such as (irrigation) water, through the smart use of crop combinations that, together, are less water demanding.

Photo: Crop and varietal diversity at a food and seed fair, Chimikuko, Zimbabwe (May 2022). Credit: Bioversity International/R. Vernooy

Yield data collected by Community Technology Development Organisation (CTDO) of Zimbabwe from smallholder farmers in Rushinga and Mt Darwin consistently demonstrate that despite rainfall variability and effects of extreme weather events, small grains such as millets and other traditional crops are doing very well in comparison to crops such as maize. Thus, crop diversification is providing a fallback option for the farmers, notably in times of drought.

Other research by CTDO in Zimbabwe confirms that production of a diverse range of crops on the same piece of land, in combination with improved agronomic practices, results in improved yields. Experience from Mutoko, Mrewa and Uzumba-Maramba-Pfungwe (UMP) has shown that when crop diversification is used, cycles of pest and diseases are interrupted, weeds are suppressed, and soil water moisture retention is increased. The growing of trap crops, such as sunflower or sorghum at a farm, helps to eradicate Striga – a devastating parasitic weed in Africa and parts of Asia affecting cereals. The inclusion of leguminous crops such as Bambara nut, bean, cowpeas, groundnut, in diverse cropping systems has resulted in improved soil fertility, reducing the need to apply nitrogen, and reducing input costs.

Kenya, Tanzania, Uganda: mobilizing and evaluating new diversity

In East Africa, agricultural production rates are low, exacerbated by frequent erratic rainfall and droughts. The loss of genetic diversity in farmers’ hands has greatly narrowed the gene pool from which they choose varieties that do well in challenging environments.

To strengthen farmers’ adaptive capacity, a collaborative initiative was implemented in Kenya, Uganda and Tanzania by national research organizations, farmers and their community seed banks, non-government organizations, and the Alliance of Bioversity International and CIAT. Through targeted sourcing and pooling of germplasm from the three national genebanks of Kenya, Tanzania and Uganda, organized farmers worked together with breeders to evaluate, on-station and on-farm, the best performing varieties of bean, finger millet and sorghum, based on locally relevant criteria.

After several cycles of testing, several best performing varieties were selected in each country, increasing the availability and diversity of climate-smart varieties of bean, finger millet and sorghum. Farmer groups have initiated seed production of these top varieties and are also exploring value addition options to business and generate income.

Zimbabwe: Participatory variety selection

Community Technology Development Organisation (CTDO) of Zimbabwe is working with smallholder farmers to breed crop varieties that are adaptable to their local micro-climates. Participatory varietal selection is a process where farmers through the farmer field school approach (FFS) select crops and/or crop varieties that perform best in their local environments, based on their own preferred traits, e.g. early maturing, good yield, large grain size, pest and disease tolerance, taste, straw production.

CTDO, in collaboration with the crop breeding institutes of Zimbabwe and CGIAR centers in the country, have assisted in organizing farmers in FFS for participatory varietal selection (PVS). Smallholder farmers were provided with released lines of preferred crops, in this instance, groundnut, pearl millet and sorghum, for evaluation on their farms and in the local communities.

Photo: Improved pearl millet lines for evaluation by the Farmer Field School, Rushinga, Zimbabwe. Credit: Bioversity International/R. Vernooy

PVS gives smallholder farmers the opportunity not only to evaluate developed crop varieties (or varieties still under development, e.g. improved lines), but also to have access to adaptable seed. Selected varieties are multiplied within the FFS and the seed shared among community members creating much needed seed security. Seed is also conserved in the local community seed bank.

In Rushinga district, Mashonaland, central province of Zimbabwe, FFS worked with breeders on developing new pearl millet varieties. They started with 10 lines and at the end of four years, farmers adopted the three best performing lines adopted. These varieties successfully passed several cycles of farmer testing (women and men farmers participated), addressing climate change induced challenges, and bringing new and better adapted crop diversity to the communities.

Photo: Explaining the pearl millet experimental design managed by the Chimikuko Farmer Field School. Credit: Bioversity International/R. Vernooy

Insights

Mobilizing crop and varietal diversity can generate multiple benefits for farmers, their communities and organizations. These include better performing crops/varieties that have higher yields, are more nutritious, generate higher market prices, and are better adapted to climate changes and related uncertainties and risks. Increased diversity maintained in community seed banks can also serve as an insurance for future needs and as inputs for further crop experimentation and improvement. Farmers’ active engagement in the action research process can strengthen their experimentation and innovation capacities; an unplanned, but useful benefit.

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